Mental health fears over IVF

IVF Procedures may cause genetic abnormalities that lead to long-term health problems for the unborn baby, according to researchers.

They say the common practice of storing fertilised embryos can provoke genetic changes that may develop into mental and behavioural disorders later in life.

Their findings come amid mounting concern over the health problems of test-tube babies.

They have warned IVF clinics to avoid keeping fertilised embryos for longer than necessary.

In UK laboratories, embryos are often cultured for five to six days after fertilisation so they can start to divide and grow under close supervision.

Only the healthiest embryos survive to the "blastocyst" stage - when they are a tiny ball of 60 cells - and are then hand-picked to boost pregnancy rates.

But this storage period could ultimately harm the baby, the U.S. study suggests. Scientists from the University of Pennsylvania studied the behavioural patterns of mice created through IVF treatment.

Research leader Professor Richard Schultz, says: "Modest alterations in the environment experienced by the pre-implantation embryo can have long-term consequences.

"This finding may be especially important in the context of treating human infertility by using assisted reproductive technology [such as IVF] which inevitably entail embryo culture."

73,000 IVF babies since 1991

As many as 8,000 British babies are born through IVF each year. Some 73,000 have been born since 1991.

The practice of culturing the fertilised embryo for five or six days has become increasingly popular because it avoids multiple pregnancies, which carry their own health risks. Instead of implanting two or three embryos, couples can wait to select the one which is showing the best potential.

But little is known about the long-term consequences of keeping embryos in the laboratory. Previous studies have shown that mouse embryos stored in culture mediums can develop faulty genes.

The University of Pennsylvania team studied the behaviour of mice whose embryos were stored in the laboratory before being implanted in the womb of a foster mother. They were compared with those whose embryos developed naturally in the womb before being transferred to a foster mother.

The mice whose embryos had been stored began to show behavioural abnormalities at four to six months. They had a significant decrease in memory and lacked awareness and a sense of danger. They were more restless than those which had developed naturally in the womb. They also behaved abnormally, suggesting deep-rooted mental changes.

Dr Ted Abel, co-author of the report, said: "Decreasing the length of time between fertilisation and implantation and further refining the composition of the culture medium are two ways that may mitigate risk."

Growing concern over test-tube babies

The findings - reported today in the journal Proceedings of the National Academy of Sciences - reinforce a growing body of evidence that test-tube babies are not as healthy as those conceived naturally.

Scientists already know that freezing embryos for months or years for future IVF treatment can lead to problems.

A study published last October found that a third of women who became pregnant through IVF lost their baby to an ectopic pregnancy, which occurs when the fertilised egg implants outside the womb.

Dr Richard Kennedy, secretary of the British Fertility Society, said: "There have been concerns raised that extended culture gives rise to certain changes which can adversely affect embryo development.

"This study provides a bit more information which suggests it may not be the best thing for embryos."